Resilient liner and cap for closing containers



June 8, 1965 HQ. DORN 3,187,920

RESILIENT LINER AND CAP FOR CLOSING CONTAINERS Filed July 23. 1962 2Sheets-Sheet 1 l4a. q C$ Ila-3 INVENTOR HENEYJDOZH BY 4 2a., PJW

ATTORNEYS June 8, 1965 H. J. DORN 3,187,920

Filed July 2:5, 1962 2 s hhhhhhhhh et 2 4o f7. lea 22a. 27 am mvmonHemzv J; DOIZN 4D II BY M 24, W

ATTORNEYS United States Patent 6 O This invention relates to resilientliners employed for seals over the mouths of bottles and likecontainers, and

to the forming of the same. i

It is known, in the Schneider United States Letters Paten 2,752,059, toplace a mass of plastisol in a cap member and shape the mass under heatand pressure to form a liner which has a thin central portion extendingover the container mouth and an annular portion of greater aver agedthickness and formed by concentric projecting ribs alternating withgrooves. These ribs are shown'as of essentially the same height from theinner surface of the cap member. During application to the container,the ribs encounter the lip or curvatureroll around the bottle mouth: aspressure is exerted in the axial direction of the container, the ribsare deformed elastically and conform to the lip so that, when a crowncap is crimped to the container ring, a maintained sealing effectresults for re- 3,187,920 Patented June 8, 1965 and downward conicalsurface 13 a groove 14 in which a rib can be molded in the liner. Thisgroove illustratively has a depth from the reference plane of surface 10of 0.031 inch, with the surface 13 at an angle of 45 degrees to thereference plane. The bottom or root 15 of the groove 14 may have aradius not greater than 0.005 inch provided that the aforesaid depth of0.031 inch is present in the illustrative practice.

The surface 13 joins a second upwardly and outwardly conical surface 17at a ridge 16 which is 0.005 inch above the reference plane, with thesurface 17 at an angle of 45 degrees to such plane. The surface 17 joinsa second outwardly and downwardly conical surface 18 at a groove root 19to provide a second groove 20 with the groove root 19 at 0.017 inchabove the reference plane. The surface 18 is at 45 degrees to thereference plane, and joins a third upwardly and outwardly conicalsurface 21 at a ridge 22 which is 0.005 inch above the reference plane.

The surface 21 joins a third downwardly and outwardly conical surface 23at a groove root 24 to provide a third groove 25. The surface 23 at acorner 26 joins a plane annular surface 27 which is parallel to and0.008 inch sisting movements of and in the cap due to internal pressurein the container, for example.

It has been found that a superior type of sealing can be attained byhaving a first rib of greater height for first engaging the containerlip, to be resiliently compressed thereagainst, and at least one otherand lower rib located farther from the container axis and alsoresiliently compressed against the container lip during sealing.Therewith, during the closing and sealing, a compressed elastic annularmass fills the space between the container lip and the cap, with theportion of the annulus nearer the container contents under a greaterelastic force than a portion farther from such contents.

An illustrative embodiment of the invention is shown on the accompanyingdrawings, in which:

FIGURE 1 is a diametrical sectionthrough a punch for forming a crownliner of the instant invention;

FIGURE 2 is a diametrical section of a crown closure shell on a platenand containing a mass of moladble liner material;

FIGURE 3 is a diametrical section of a crown closure shell with a moldedliner therein, and with the outline of a standard bottle section shownin dotted lines;

FIGURE 4 is a diametrical section showing the crown closure in sealingposition on a bottle; a

FIGURE 5 is a section corresponding to a part of FIGURE 1, and on agreatly enlarged scale;

FIGURE 6 is a corresponding enlarged section corresponding to a part ofFIGURE 3.

Itis customary to mold liners in crown shells with the shell cavity openupwardly, and such is the position of parts in FIGS. 1 to 3. The closedand sealed bottles are usually stored with their mouths upward, and suchis the position in FIG. 4. The several figures show sections; and itwill be understood that the standard circular shapes about the'bottleand shell axis A are present, and that the above the reference planeand'illustratively is 0.011 inch wide in the radial direction of thepunch. The outer edge 28 of the surface 27 is formed at a fourthupwardly and outwardly conical surface 29 at 45 degrees to the referenceplane andendingat a second plane annular surface 30 which can be 0.006inch wide in the radial direction of the punch, and located parallel toand 0.031 inch above the reference plane 10. The outer edge 31 of thesurface 30 is formed by an outer cylindrical surface 32 of the punch,which is joined by the curved surface 33 to the'cylindrical surface 34with the maximum diameter of 1.0525 inches for the punch, at the edge35. The surface 32 can havea diameter of 1.029 inches, being smallerthan the larger diameter TC and greater than the smaller diameter BC ofthe crown shell referred to the general axis A of the shell, liner andbottle, for the smooth portion of the shell below (FIGS. 2 and 3) thecorrugated portion of the shell skirt and at top corner radius portionTCR.

The crown shell CS of FIG. 2 is illustratively of metal, and has anupwardly concave central domed portion CD which originally can have aradius of 6 to 8 inches. This portion CD merges smoothly into thetopcorner radius portion TCRyabove which, in FIG. 2, are shown thecorrugated edge structures CE.

In forming the crown liner in such a crown shell, a measured quantity ofa ther-mo-plastic material is deposited as a mass PM on the centralportion CD of the shell, while the shell is illustratively positioned ona platen BP. The punch P and the platen are heated: such is known, andthe specific heating means is not shown.

The mass PM may be of a plastisol, for example of fine particles ofvinyl chloride polymer resin in a plasticizer therefor-such as dioctylphthalate. At room temperature, and up to about degrees R, such aplastisol behaves as 'a viscous liquid, essentially withoutinterditfusion of the resin and plasticizer. At higher temperature, e.g..275 to 375 degrees F., inter-solution begins, and the plasticizercomponent becomes more viscous but still capable of flow under pressureat such temperature,by the dissolution of the polyvinyl resin therein:and the hard particles of polyvinyl resin become softer by thepenetration of the plasticizer into them. When an appropriate time ofheating at the selected temperature has occurred, the inter-diffusionproduces essential uniformity homogeneity in the mass. For commerciallyavailable plastisols, this may be 3 to 15 seconds at 300 degrees F., or1 to 5 seconds at 350 degrees F.; and such complete dissolution of onecomponent into the other completely inter-dissolved and cured mass iselastic, and

returns resiliently when deformed by pressure. Such commercialplastisols'ha've the polyvinyl resin particles and the plasticizer ascomponents; and also often include inert filler particles, waxes and thelike to prevent blocking and facilitate the flow during molding, andcoloring matter. A property of such plastisols is that of liquidity asdelivered and employed for forming the sticky masses PM. Upon'hea'ting,the .mass becomes more viscous and form-maintaining, and adheres to' theinner surface of the crown shell: such'shells may have" a baked coatingof vinyl lacquer; The heating may occur in a single stage or in severalstages. For example, thernass PM maybe deposited, and, then the shellregion CD heated while the hot punch ,P is lowered into the shell, toengage and cause the liquid: mass; to spread radially as indicated bythe arrows in FIG. 2. Shortly thereafter, the edge 31 of the punch comesinto contact withth'egshell wall, below its corrugations; and actsmechanically to force the periphery of the crownfshell dowriWard,-'while the center of the domeportio'nTCD, isdetained' by theplaten,xsothat the radius of the dome is increased. Therewith theradiall'y'spreading mass is confined by the engage'ment of the punchedge 31*with the shell, so that flowing material is restricted: againstflow. beyondth'e edge 31, and instead is caused to become distributedbetween the punch and the shell. As the; punch moves downward, thevolumeofthe space .betweenthe punch and shell decreases: and also theflattening of the dome at'portion CD acts todecrea'se the volume.Ultimately; the volume available is reduced to that required for thequantity originally deposited as the mass PMg at which state themasshas' been distributed to fill the volurne. Further downwardni'overn'ent'is then restricted, so the,

in practice the punch or platen is spring-mounted so that furtherpressure does not produce change of their relative positions; Thehotpuncl'f and shell areheld in confact' with the mass, after itsshaping, until the curing is coni'p'lete.

In another practice; the" she'llwith the rnassf therein; as in FIG. 3,is heated" until partialinter-dissolutionhas occurred; and then thepunch is brought down, with heat and pressure, so' the' partially cured,adherent, and normally form-maintaining mass is caused to flow and tillthe space between the'punch and the shell. These practicesmay'be'modified, ,and the punch time shortened, by withdrawingthe" punchafter the mass has been shaped and has been rendered non-tacky and formmaintaining in its-sh'apedcondition; and then the shell with the shapedliner therein is further heated, as in a hot air oven, to complete thecuring. r i A further practice is to heat the assembly of FIG. 2 untilthe mass PM'is completely cured: and'then engage the punch P under lieatand pressure for thermosoftening the elastorner and effecting theshaping of the liner. r

In each practice when the mass PM is in position, the

edge 31, FIG. 5, preferably, comes into contact with the inner surfaceof the metal shellbefore' parts of this mass,

7 displaced outwardly by thepunch pressure, come to the edge 31 notingthat the grooves 14, 29,25 successively receive the material.Concurrently with or shortly after the corresponding shape aftercompression and crimping in FIG. 4.

In practice with crown closures having liners with concentric ribs withtheir crests. or ridges at a common plane or in a common conicalsurface, the sealing per- :formaince is excellent with new, undamagedbottles. With trade-returned bottles, for beverages under pressure,troubles have occurred when the bottle lip has been chipped. Thedifiicult'ies' were particularly noted with beer bottles; the gasescapes andthe pressure was lost, even without visual indication ofliquid leakage. On study, much of the trouble occurred with bottleschipped around the outside of the lockingring. Increase of the amount ofresilient material adjacent a the top corner radius, so the regionbetween the outside of the bottle lip and the inside of the metal skirtis filled with sealing compoundunder pressure as the bottle leaves thecrimping operation, did not solve the troubles By deepening mass acts asan essentially". incompressible,material: and

In the event the mass PM is not concentric with the axis a Therelationship of theribs or ringsto thetop' of the lip BL of the standardbottle is shown in FIG. 3; and

the grooves and ridges and the base thickness from the roots of thegrooves and the metal shell, to augment the axial distance of resilientaction of the. liner, thenumber of defectively sealed chipped bottleswas reduced; but other troubles were then noted. Crowns with this deeper'ring designwere more susceptible to side-hit abuse: that is, a blowagainst the side Wall or crown skirt could cause. pressureloss' Further,whenthe filled and capped bottles were dropped through ,caser. grids foralignment of a group of bottles in a case,the edge of the crown was moreapt to' catch on the grid or other projection, with disturbance, to theseal.

It has been found th'atthe difiiculti'es canbe. overcome, by reducingthe base thickness'between the groove roots and the metal shell,b'yha'ving; an inside rib higher than outer ribs and positioned' toengage the top; of the bottle'lip, by reducingthe amount of material atthe peripheral edge of the lin'enand by providingtwo lines" ofengagement of the peripheryof the molding punch with the inner surfaceof the closure shell. The changes in the heights of the sealing rings orribs and the greater depths of the grooves between the rings givelagreater, e.g. twice as much, downward movement of the closure shellunder the axial pressure during b'ottle. closing, as the resilientmaterial isrnore' free tomove. The reduction of the amount of materialat the edge of the liner assures that the clinching or crimping of theskirt corrugations radially inward and beneath the locking ring ofthebot-, tie occurs with an axial component of force against the reactionof the compressed sealing rings and thus to the top of the bottle lip;without being reduced by compression of material between the outside ofthe lip", and the top corner radius of the cap, and the establishment ofa fulcrum line at that region. The presence of the double engagement ofthe punch with the shell, during the shaping of the liner, provides aperipheral pocket space between thetwo lines of engagement or danis, inwhich any flash forces beyond the inner line is distributedipefipherally, instead of moving axially along the skirt arid into the skirtcorrugation areas" where it' is present between the skirt and lockingring and can prevent a tight niet'alto-glass crimping upon a bottle.

Of the several changes, the 'ernplo'ymeritof' a deep rib 1421 on theliner, for engagement with the top, of the container lip (F164) sothatit bends andld'forms under the capping pressure, and with a radially"outward groove and rib for completing .the' sealing annulus, has beenfound most important. During. the distortion under, cappingpressure,'the shallower rib actstoprovide a resilient resistance tooutward expansion of the deeper rib:

and together they establish an essentially solid but elastic shell, andcan have the form shown in FIG; 6, it beingunderstood that theflattening of the dome portion CD of the shell is not necessarilyfollowed by return to the original radius of curvature when the punch isretracted upwardly but this portion can be flatter. In the illustrativeembodiment, a standard crown shell CS is in dicated, with the centraldome portion CD having a cross-sectional curvature of FIG. 2 with radiiof 6 to 8 inches when the plastisol is inserted, and being modified bythe action of the molding punch so the radii are 10 to 11 inches inFIGS. 3 and 4.

' The thickness of the central portion 40 of the liner, Within theinside ring or rib, can be 0.005 inch. In FIG. 6, the parts of the linerare shown as produced by the mating parts of the forming punch of FIG.5: thus the groove 14 of the punch provides the inner rib or ring 14a ofthe liner, the ridge 16 of the punch provides the groove root 16a of theliner, and so on. The roots 16a and 22a are about 0.009 inch from theinner surface of the metal shell, in the illustrated form; the surface27a is at a lesser distance due to the curvature of the shell.

The portion 2% along the top corner radius can be less than 0.005 inch:its presence being preferred to assure liner adhesion outside the regionof the surface 27a. The region 32a indicates a minor local flash whichhas passed beyond the engagement 31a on the shell by the edge 31 on thepunch: noting that this is below the second damming point 35a.

During capping, the ribs 14a, a and a are engaged with and compressedagainst the top of the bottle lip BL, as shown in FIG. 4. The materialof these ribs spreads radially inward and outward under the compressionforces. The crimping tool acts against the periphery of the corrugatedregion CE of the shell skirt, as indicated by the arrows in FIG. 4, tocause parts CC of the corrugations to engage beneath the locking ring LRof the bottle. It will be noted that the masses 29a, 32a of FIG. 6 arenot active, in FIG. 4, to deflect or divert the crimping forces uponparts CC from cooperating with the axial forces of the seating ram,shown as arrow SR, in assuring maintenance of the seal at the annularcompressed mass SM provided by the several ribs. In FIG. 4, the lines50, 51, 52 respectively represent the prescribed standard or normalshape of the bottle lip, the permissable largest mouth size, and thepermissable smallest mouth size. In each instance, it will be noted thatall ribs act against the top of the lip.

It will be understood that the illustrative practice is not restrictive,and that the invention can be practiced in other ways within the scopeof the appended claims.

What is claimed is:

ll. A resilient liner and cap structure for closing a container,comprising a cap having a peripheral skirt and a central wall portion,and a liner of elastic material in said cap, said liner having at leasttwo concentric ribs for engaging an upper surface of the lip of thecontainer to be elastically compressed thereagainst, the radially inwardrib being deeper than the radially outward rib whereby the inner rib isfirst engaged with-the upper surface of the container lip and isflattened and compressed thereagainst before the outer rib encountersthe container lip.

2. A resilient liner and cap structure for closing a container,comprising a cap having a skirt and a central wall portion and a topcorner radius portion merging with the skirt and the central wallportion, and a liner of elastic material in said cap and extending overand adhering to the central wall portion thereof, said liner having aplurality of concentric ribs all located for engagement with a top ofthe lip of the container to be elastically compressed against anddeformed thereby, the radially inward rib being deeper and having agreater cross-section of the material and separated from the nextoutward rib by a groove whose root is spaced from the adjacent capsurface, all said ribs being located radially inward from the cap skirtso that upon compression against the top of the container lip they forman essentially solid mass of elastic material between the container lipand the adjacent parts of the top corner radius and central wall portionof the cap and with said mass spaced from the engagement of the cap withthe container.

3. A sealed assembly of a container and a lined cap structure, thecontainer having a lip surrounding its mouth and a locking ring, saidcap structure including a central wall portion extending over thecontainer mouth, a corrugated skirt in crimped engagement with thelocking ring, and a top corner radius portion merging with the centralwall portion and terminating short of the corrugations of the skirt, anda liner adherent in said cap, the invention which comprises the presenceof an annular part of said liner as a compressed elastic mass betweenthe container lip and the cap structure, the annular portion of saidmass adjacent the container mouth exhibiting greater elastic forces thanother parts of said mass, and the mass having annular regions exhibitinghigh elastic forces alternating with annular regions of less elasticforces, with the space between the container and the cap between the topcorner radius portion and the skirt corrugations being free ofcompressed liner material.

4. A resilient liner and cap structure for closing a container of thetype having an open mouth of predetermined diameter and a lip portionsurrounding said open month, said lip portion having a predeterminedinner and outer diameter and said inner diameter being equal to thepredetermined diameter of said month; said liner having a plurality ofconcentric ribs located for engagement with the lip portion of thecontainer, the radially inward rib being deeper and having a greatercross-section than the rib adjacent to and outwardly spaced therefrom,said radially inward rib having a diameter larger than the predetermineddiameter of said mouth.

5. A resilient liner and cap structure for closing a container of thetype having an open mouth of predetermined diameter and a lip portionsurrounding said open month, said lip portion having a predeterminedinner and outer diameter and said inner diameter being equal to thepredetermined diameter of said mouth; said liner having a plurality ofconcentric ribs, the radially inward rib having a greater cross-sectionthan the rib adjacent to and outwardly spaced therefrom, said radiallyinward rib having a diameter larger than the predetermined diameter ofsaid month, said plurality of concentric ribs being located forengagement with the lip portion of the container between the inner andouter diameter of said lip portion, the rib adjacent to the innerdiameter of the lip portion being deeper than the other of said ribs.

References Cited by the Examiner UNITED STATES PATENTS 2,752,059 6/56Schneider. 2,768,762 10/56 Guinet 215-40 FOREIGN PATENTS 6/55 France.

(2nd addition to No. 1,054,118)

Examiners.

1. A RESILIENT LINER AND CAP STRUCTURE FOR CLOSING A CONTAINER,COMPRISING A CAP HAVING A PERIPHERAL SKIRT AND A CENTRAL WALL PORTION,AND A LINEAR OF ELASTIC MATERIAL IN SAID CAP, SAID LINER HAVING AT LEASTTWO CONCENTRIC RIBS FOR ENGAGING AN UPPER SURFACE OF THE LIP OF THECONTAINER TO BE ELASTICALLY COMPRESSED THEREAGAINST, THE RADIALLY INWARDRIB BEING DEEPER THAN THE RADIALLY OUTWARD RIB WHEREBY THE INNER RIB ISFIRST ENGAGED WITH THE UPPER SURFACE OF THE CONTAINER LIP AND ISFLATTENED AND COMPRESSED THEREAGAINST BEFORE THE OUTER RIB ENCOUNTERSTHE CONTAINER LIP.